Thermostat



(No Model.)

W. E. LEWIS.

THERMOSTAT.

Patent-ed Feb. 26,

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inrTn STATES PATENT Cierres..

WILLIAM E. LEVIS, OF CORRY, PENNSYLVANIA.

TH ERMOSTAT.

SPECIFICATION forming part of Letters Patent No. 398,740, dated February26, 1889. Application filed February 23, 1888 Serial No. 265,025. (Nomodel.)

mostat, of which the following is a specitication,

This invention has relation to improvements l in apparatus whereby thetemperature of an apartment may be maintained at a uniformlydetermineddegree by the automatic regulation of the suppl y of the heating medium.

The invention will be full y understood from the fcllowing descriptionand claims, when taken in connection with the accompanying drawing, inwhich the figure is a vertical longitudinal sectional view of athermostat embodying my improvements.

Referring by letter to the said drawing, B indicates a metallicreservoir, which is here shown as of a cylindrical form, and which isdesigned to be illed with any7 suitable liquid having a high degree ofexpansibility. This reservoir is closed at its upper end by a cap, A,designed to tit tightly therein, so as to torni an air-tight joint withthe said reservoir. This cap A is provided with a filling-aperture, C,and which is closed by a screw-plug, D. The cap is furthermore providedwith an outletaperture, E, which extends through a lateral horizontalbranch, as shown at H', which branch is externally threaded, as shown,to receive a union, F, whereby a connection is had with one end ot apipe, Z, a packing, G, being interposed at the union before mentioned.The lower end ot' the reservoir has firmly fixed to it a plate, ll,which is recessed annnlarly, as shown at J, and in this recessed portionet the said plate is secured a diaphragm, N, pre'l'eralily ol' metal.This plate i also provided with screw-lunes in its niargin 'for theattachment ot the bottom plate, l, which has similar apertures toreceive the conueetiiig-screws l. This bottom plate, l, has acentrally-distended hollow portion, P, for the reception ot' a headednut, M, which nut is secured to the under side of the diaphragm and isdesigned to move with it.

S indicates a regulating-screw, which is provided for the greaterportion of its length lwith right-hand threads, R, and its upper end isreduced, as shown at o, where it is provided pushed inwardly,

i with left-hand threads, or th reads which run in an opposite directionto the right-hand threads. This screw is seated in a screw-tappedaperture in the lower end of the bottoni plate, l,

and its upper reverscly-threaded portion engages threads in the nut M.By turning the screw to the rightthe diaphragm N will be forcedoutwardly, slightly increasing the size ot' the reservoir B anddiminishing the pressure of the liquid therein, while by turning thesaid screw to the lett the diaphragm will be which will cause apressure,and by means ol' which the apparatus can be set for diiierent degrees oiheat.

T indicates a valve-chamber having inlet and outlet ports of the usualtorni, which ports are internally threaded to receive connectingpipesJfor the delivery of gas or other combustible iuid.

Screwed in the breast oi the valve case or trame is a plate, D2, havinga chamber therein to receive a spiral spring, which surrounds thevalve-stem, as shown, and presses against a head on the said stein, soas to normally keep the fuel-passage open. This plate D2 is providedwith threaded apertures in its inargin to receive fastening-screws,which pass through an upper plate, D. This plaie D is recessed in itsunder side, and in the recess is secured a diaphragm, D4, which isdesigned to be held normally raised by the action of the springsurrounding the valve-stein. This plate D is also provided with acentral inlet-aperture, D5, around w iich are formed external threads toreceive a packing-gland, C, which latter also serves as a means oi'uniting the said plate with the lower end of the tube Z.

instead of using liquid in the reservoir air may be used.

In operation, after the parts have been properly connected, thescrew-plug D is removed until the reservoir has been filled with liquidup to within about one inch of the top. The plug D is then screwed down,and the apparatus is ready for lifted by the action of the spring, so asto allow the gas to iiow for heating purposes. Then the liquid hasbecome sui'cieiiitly warm or hot and begins to expand, it will pass outof the reservoir through the opening E, and thence down the pipe Z uponthe diaphragm beneath the same, thereby seating the valve use, and thevalve held TOO and checking; the ilow of gas, the diaphragm of the mainreservoir bein g regulated by means of the right-and-left-threaded rodS.

Having described my invention, what I claim is l. In a thermostat, thecombination, with a reservoir constructed as desoribed and provided withthe dia1i)hragm at its lower end, of the threaded nut beneath thediaphragm and the right-an(l-left-threaded regulating-screw tapped inthe bottom oi' the said reservoir and engaging the said nut,substantially as speeifled.

2. The Combination, with a reservoir constructed as described, of theoap inV the upper end of the said reservoir having a filling-apertureand the lateral branch provided with an

